The stock controller uses a single layer, single sided board. There’s a resin-blob chip, but also an SOP-20 microcontroller. Since [Todd’s] using several strings of lights on his house, he wondered if it would be possible to improve on the controller in order to synchronize the strands. His investigation showed that the board was designed to host a crystal oscillator but it is unpopulated. Unfortunately you can’t just add those parts to improve the timing of the chip (firmware changes would also be requires). He found that there’s a spot for a push-button. Quickly shorting the pads cycles through the effects, shorting them for a longer time turns off the string of lights. There is wireless control, but it seems that the only functionality it provides is the same as the unpopulated switch.

We enjoyed the close-up circuit board photos, and we like the spacing jig he used to attach the lights to his fascia boards. We’ve embedded a lengthy video about his exploits after the break.

I just saw these at the mall today… The model I saw had a crystal-clear casing, so I could see what appeared to be a small 8 pin microcontroller, on top of a 1×10 array of SMD led’s.

If you’re just interrested in making the same circuit, then with charlieplexing, it’s quite easy to cycle say 20 LEDs with 5 pins of a typical attiny13. there are plenty of articles about charlieplexing on this site.

That was the most interesting thing I have ever seen about a single strand of Christmas lights. I doubt he is the type of person GE had in mind during design. Does he really think people are going to see these elsewhere and not want to buy them? Most people don’t care enough to ask the home owner what model of lights they have. They don’t even care to pick them over in the store. They’ll just grab some lights that they looked at for a good 30 seconds. The phrase “over thinking” comes to mind when watching the video.